Computer systems can be viewed as containing resource entities of various types that are used by resource user entities to provide a particular service. Typical resource entities (or simply ‘resources’) include entities for running programs, storing data, providing communication, or performing some other function, such as encryption/decryption. A resource user entity (or more simply ‘resource user’) can, for example, be constituted by an application program providing a particular service.
Typically, multiple resource users will exist concurrently in a computer system with the current population of resource users changing over time according to the needs of human end users; this is particularly the case if the computer system is a very large facility such as a data center. Also, from time to time a resource will fail to operate correctly and need to be replaced; conversely, a resource user may fail, effectively freeing up the resources it was using. For the foregoing reasons, the allocation of resources to resource users needs to change over time and this must be managed appropriately. In particular, resources must be allocated in way which ensures that each resource user is aware of the resources that have been allocated to it and can use them, and that the system does not lose track when failures occur. The role of managing resource allocation is carried by one or more resource managers; of course, where multiple resource managers are used, the problem of coordinating resource allocation becomes even harder.
Past attempts to solve this problem have typically relied on an inventory or a similar representation to maintain information about the resources and their allocation.
It is an object of the present invention to provide a way of managing resource allocation that facilitates the provision of allocation information to entities that require to know such information.